1 files changed, 54 insertions, 26 deletions

diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
index 397540a4b799..4f063fb1c6b4 100644
--- a/drivers/perf/fsl_imx8_ddr_perf.c
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -361,25 +361,6 @@ static int ddr_perf_event_init(struct perf_event *event)
 	return 0;
 }
 
-
-static void ddr_perf_event_update(struct perf_event *event)
-{
-	struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
-	struct hw_perf_event *hwc = &event->hw;
-	u64 delta, prev_raw_count, new_raw_count;
-	int counter = hwc->idx;
-
-	do {
-		prev_raw_count = local64_read(&hwc->prev_count);
-		new_raw_count = ddr_perf_read_counter(pmu, counter);
-	} while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
-			new_raw_count) != prev_raw_count);
-
-	delta = (new_raw_count - prev_raw_count) & 0xFFFFFFFF;
-
-	local64_add(delta, &event->count);
-}
-
 static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config,
 				  int counter, bool enable)
 {
@@ -404,6 +385,56 @@ static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config,
 	}
 }
 
+static bool ddr_perf_counter_overflow(struct ddr_pmu *pmu, int counter)
+{
+	int val;
+
+	val = readl_relaxed(pmu->base + counter * 4 + COUNTER_CNTL);
+
+	return val & CNTL_OVER;
+}
+
+static void ddr_perf_counter_clear(struct ddr_pmu *pmu, int counter)
+{
+	u8 reg = counter * 4 + COUNTER_CNTL;
+	int val;
+
+	val = readl_relaxed(pmu->base + reg);
+	val &= ~CNTL_CLEAR;
+	writel(val, pmu->base + reg);
+
+	val |= CNTL_CLEAR;
+	writel(val, pmu->base + reg);
+}
+
+static void ddr_perf_event_update(struct perf_event *event)
+{
+	struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 new_raw_count;
+	int counter = hwc->idx;
+	int ret;
+
+	new_raw_count = ddr_perf_read_counter(pmu, counter);
+	local64_add(new_raw_count, &event->count);
+
+	/*
+	 * For legacy SoCs: event counter continue counting when overflow,
+	 *                  no need to clear the counter.
+	 * For new SoCs: event counter stop counting when overflow, need
+	 *               clear counter to let it count again.
+	 */
+	if (counter != EVENT_CYCLES_COUNTER) {
+		ret = ddr_perf_counter_overflow(pmu, counter);
+		if (ret)
+			dev_warn_ratelimited(pmu->dev,  "events lost due to counter overflow (config 0x%llx)\n",
+					     event->attr.config);
+	}
+
+	/* clear counter every time for both cycle counter and event counter */
+	ddr_perf_counter_clear(pmu, counter);
+}
+
 static void ddr_perf_event_start(struct perf_event *event, int flags)
 {
 	struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
@@ -537,7 +568,7 @@ static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
 {
 	int i;
 	struct ddr_pmu *pmu = (struct ddr_pmu *) p;
-	struct perf_event *event, *cycle_event = NULL;
+	struct perf_event *event;
 
 	/* all counter will stop if cycle counter disabled */
 	ddr_perf_counter_enable(pmu,
@@ -547,7 +578,9 @@ static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
 	/*
 	 * When the cycle counter overflows, all counters are stopped,
 	 * and an IRQ is raised. If any other counter overflows, it
-	 * continues counting, and no IRQ is raised.
+	 * continues counting, and no IRQ is raised. But for new SoCs,
+	 * such as i.MX8MP, event counter would stop when overflow, so
+	 * we need use cycle counter to stop overflow of event counter.
 	 *
 	 * Cycles occur at least 4 times as often as other events, so we
 	 * can update all events on a cycle counter overflow and not
@@ -562,17 +595,12 @@ static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
 		event = pmu->events[i];
 
 		ddr_perf_event_update(event);
-
-		if (event->hw.idx == EVENT_CYCLES_COUNTER)
-			cycle_event = event;
 	}
 
 	ddr_perf_counter_enable(pmu,
 			      EVENT_CYCLES_ID,
 			      EVENT_CYCLES_COUNTER,
 			      true);
-	if (cycle_event)
-		ddr_perf_event_update(cycle_event);
 
 	return IRQ_HANDLED;
 }